1. Field of the Invention
The present invention relates to a method and apparatus for controlling the data rate in a network and more particularly to a method and apparatus for controlling the data rate between two processors on an Internet protocol network by adding a fixed latency
2. Discussion of the Background
While a number of different types of network systems are in use, one of the common arrangements is a network based on the TCP/IP (transmission control protocol/internet protocol). This combined protocol is used to implement the Internet and also private networks such as Intranets. This arrangement provides for reliable delivery of sequenced packets of information across the Internet. An acknowledgment system is utilized so that the sending device will know that the data has been received. A timing mechanism can be used so that if an acknowledgment is not received within a certain amount of time, the packet is retransmitted. This particular system is well known and widely used.
An example of such a system is shown in FIG. 1 where an Internet protocol network 10 is shown connecting a client processor 12 with various server processors 14 and 16. The network includes routers 18 and 20 which control the flow of data on the network. One problem which can occur is the overloading of the router which causes it to crash when the data rate increases temporarily beyond the capability of the router. This problem has sometimes been addressed by attempting to control the data rate in the network.
U.S. Pat. No. 6,115,357 which is assigned to Packeteer, Inc., describes the use of TCP/IP protocols and their use in networks. This device attempts to pace the data flow by arranging data transmission over a period of time after determining a round trip time for the data.
U.S. Pat. No. 6,046,980, which is assigned to the same company, utilizes packet parsing based on content. That is, the packets are classified and a particular rule is applied according to their classification.
U.S. Pat. No. 6,038,216, also assigned to Packeteer, Inc. shows data rate control without data rate supervision. Latency is added to the acknowledgment packet and the size of the flow control window is adjusted to control the data rate.
U.S. Pat. No. 6,119,235 shows a method for quality of service management where the round trip time of the data is determined and delaying transmission of a receive acknowledgment signal when the bit rate is greater than a bit rate limit.
Similarly, other patents describe the measurement of the data flow in order to control in some fashion the data rate in a network.
While various solutions are possible for this type of problem, they often involve making major changes of some kind in either the client processor or the server processor which may be difficult and expensive. It would be advantageous to correct the problem merely by making adjustments of some sort in the network itself rather than requiring changes to either the client processor or server processors.